OPTIMIZATION OF PEELING TIME AND OPERATIONAL SPEED FOR CASSAVA PEELING USING CENTRAL COMPOSITE DESIGN AND RESPONSE SURFACE METHODOLOGY

The effect of two process parameters namely: peeling time and operational speed on the peeling process of cassava during cassava processing were investigated. The optimization of flesh loss from cassava was carried out using the central composite design and response surface methodology. Taking flesh loss as the response of the designed experiment, the data obtained were statistically analysed to get a suitable model for optimization of flesh loss as a function of peeling time and operational speed. The optimization produced 13 feasible solutions whose desirability is close to 1 and the selected (most desirable) condition was found to be: reaction time (3.5 mins) and operational speed (775 rpm) at a minimum flesh loss was found 38.6 %. Physical experiment was also done using cassava of average width of 60 mm and height 140 mm at different speeds of operation ranging from 350 to 750 and 1440 rpm within a resident time of 3 minutes. The optimum speed of shaft rotation was found to be 75 0 rpm with an average minimum flesh loss of 36.31% and average peeling efficiency of 63.68%. The correlation of the results obtained from both the central composite design and physical experiments validates the efficiency of the developed model. Increase i n speed and peeling time increases the peeling efficiency, however, further increase beyond the optimum reduces the peeling efficiency of the machine as the machine starts grating the cassava with significant flesh loss.